JPH0443544A - Semiconductor ceramic composite for secondary electron multiplying device - Google Patents

Abstract

PURPOSE:To obtain stable operation in ultra-high vacuum environment by subjecting a semiconductor ceramic having a suitable composition ratio of zinc oxide-titanium oxide-copper oxide to a baking process. CONSTITUTION:Zinc oxide, oxide copper and titanium oxide are prepared, and so blended as to obtain a semiconductor ceramic having a suitable composition ratio thereof. Then, the aforesaid materials are wet grindered and mixed, and further subjected to processes of dehydration, drying, pulverization and grading. A product so molded is baked in natural atmosphere, using an electric furnace, and a cylindrical semiconductor ceramic sample is thereby obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a semiconductor ceramic composition used in a secondary electron multiplier.

(Prior Art) As a secondary electron multiplier made of semiconductor ceramics, for example, Japanese Patent Publication No. 18026/1983 and Japanese Patent Publication No. 48-18
As described in Japanese Patent Publication No. 029 and Japanese Patent Publication No. 48-18030, ceramics made of zinc titanate-based semiconductor ceramics are known.

Among these, the one disclosed in Japanese Patent Publication No. 48-18026 consists of a cylinder with electrodes provided at necessary locations. Furthermore, the device disclosed in Japanese Patent Publication No. 48-18029 is a plate-shaped body provided with electrodes at both ends, and a plurality of holes are provided perpendicularly to the picture electrodes. Furthermore, the one disclosed in Japanese Patent Publication No. 48-18030 is one in which a plurality of tubes of the same length are bundled together.

Specific compositions of the zinc titanate semiconductor ceramics constituting these secondary electron multipliers include Zn072.5 mol, Ti0227.5 mol, and Zn072.
．． 5 moles, T10227.5 moles, A1.0.1.25
Consisting of moles is shown. In these two types of semiconductor porcelain, 8X10'Ω・cm, 2.8X1
It is said that a resistivity of 0'Ω"cm can be obtained.

(Problem to be solved) A secondary electron multiplier is installed in a vacuum system, and before detecting various charged particles, it is used to remove unnecessary substances attached to the multiplier. , a baking process is performed in a vacuum. This treatment is usually carried out at 100 to 350°C for several hours to about 24 hours. At this time, especially
When treated at 300°C or higher, the resistance value of the above-mentioned conventional zinc titanate-based semiconductor porcelain decreases to 1/1 of the initial value.
A phenomenon of a decrease of 0.00 to 1/1000 was observed.

For this reason, there was a problem in that a high voltage could not be applied to such a multiplier, and its range of use was narrowed.

(Means for Solving the Problems) Therefore, an object of the present invention is to provide a secondary electron multiplier that exhibits little change in resistance value and multiplication gain even when subjected to baking treatment in vacuum. do.

That is, the present invention is a semiconductor ceramic composition for a secondary electron multiplier, characterized by being made of zinc oxide-copper oxide semiconductor ceramic.

The present invention also provides a semiconductor ceramic composition for a secondary electron multiplier, characterized by comprising a zinc oxide-titanium oxide-copper oxide semiconductor ceramic.

Here, the specific composition of the zinc oxide-copper oxide semiconductor porcelain is zinc oxide as the main component, and 0.00% copper oxide added thereto.
It consists of a substance added in a range of 2 mol% or more and 50 mol% or less.

In addition, the specific composition of the zinc oxide-titanium oxide-copper oxide semiconductor porcelain ranges from 65 mol% or more to 80 mol% zinc oxide.
The main component is titanium oxide of 20 mol% or more and 35 mol% or less of titanium oxide, and 0.0 mol% of copper oxide.
It consists of a substance added in a range of 2 mol% or more and 50 mol% or less.

The reason for limiting the composition to the above-mentioned range is that in the two-component system of zinc oxide-copper oxide semiconductor porcelain, and also in the three-component system of zinc oxide-titanium oxide-copper oxide semiconductor porcelain,
This is because after baking, the change in resistivity is small and operation in ultra-high vacuum is stable.

(Effects of the Invention) According to the semiconductor ceramic composition for a secondary electron multiplier according to the present invention, the change in resistivity after baking treatment is small;
Even after the baking process, a sufficient gain for practical use can be obtained, and operation in an ultra-high vacuum is also stable.

(Example) Zinc oxide, copper oxide, and titanium oxide were prepared as raw materials to be used, and these were blended so as to obtain semiconductor porcelain having the composition ratio shown in Table 1. Put the blended raw materials into a polyethylene-lined pot mill along with agate boulders and pure water, and
At 0 o'clock, the mixture was ground and mixed. Thereafter, it was dehydrated, dried, and pulverized into 50 to 200 meshes.

A binder consisting of wheat flour paste and paraffin was added to the obtained powder to make a plastic material, which was then molded into a tube shape by extrusion molding. This molded product was placed on an alumina box spread with the material for the symbiotic material, and fired in an electric furnace at the temperature shown in Table 1 in a natural atmosphere for about 1 hour, resulting in an outer diameter of 2.0 mm.
, inner diameter 1. 0mm, length 50. A cylindrical semiconductor conductor ceramic sample of 0 mm was obtained.

Regarding the obtained samples, a voltage of 30 V/mm was applied at room temperature to measure the specific resistance at room temperature, and the results are shown in Table 1.

Further, the multiplication gain was measured using the experimental circuit shown in FIG.

In Figure 1, 1 is a cylindrical semiconductor porcelain, 2.3 is an electrode formed at both ends of the cylinder, 4 is a DC power supply connected to the electrode 2.3, 5 is a filament, 6 is a filament power supply, 7
is a power supply for electron acceleration, 8 is a collector, 9 is a collector power supply,
lo is an electronic counter. In the above circuit, all except the power supply 4.6.7.9 and the electronic counter 1o are installed in a vacuum, and the degree of vacuum is 1.0X10-
'T.

It was set as rr. Next, by setting the DC power source to 4 kV and the electron acceleration power source 7 to 200 V, the electrons emitted from the filament 5 are introduced through the entrance of the cylindrical semiconductor porcelain 1, collide with the wall surface of the cylinder, and are multiplied. The collector 8 received the double electrons, and the number of pulses was counted by the electronic counter 10 to measure the secondary electron multiplication gain.

The results are shown in Table 1.

Next, baking was performed at 4°0°C for 4 hours in a vacuum of 1,6 x 10-' Torr, and the resistivity and secondary electron multiplication gain of each sample were determined under the same conditions as above. It was measured. The results are also shown in Table 1.

As is clear from the results in Table 1, 2
According to the semiconductor ceramic composition for a secondary electron multiplier, there is no significant change in specific resistance or multiplication gain before and after baking treatment, and characteristics that are satisfactory in practice can be obtained.

(Hereinafter, blank space) In addition, although oxides were used as raw materials in the above examples,
Carbonates, chlorides, nitrates, etc. may be used as long as they become oxides upon firing. Alternatively, the fired semiconductor porcelain may be impregnated with a solution that becomes copper oxide through heat treatment, and then heat treated.

In addition to the cylindrical and linear structure shown in FIG. 1, the structure may be as shown in FIGS. 2 to 8.

That is, in FIG. 2, 20 is a flat plate made of zinc oxide-copper oxide semiconductor porcelain or zinc oxide-titanium oxide-copper oxide semiconductor porcelain, and two flat plates 20 are arranged in parallel to form a continuous path 23. was formed. Although the outer surface of the flat plate 20 may be insulated, the inner surface is exposed in whole or in part from one end of the flat plate 20 to the other. Also,
Electrodes 21 and 22 are formed at both ends of the flat plate 20.

In addition, if a plurality of electrodes are formed not only at both ends of the flat plate but also at required locations in the middle of the flat plate 20 if necessary, the multiplication efficiency can be further improved.

FIG. 3 shows a bundle of a plurality of unit tubes 30, with electrodes 31 and 32 formed at both ends. Since the cylinder 30 is entirely composed of semiconductor porcelain having secondary electron multiplication ability,
Both the inner and outer surfaces of the tube 30 have a secondary electron multiplication ability, and not only the inner surface of the continuous passage 33 of the tube 30 but also the gap 34 formed between adjacent tubes 30 serves as a secondary electron multiplication surface. can be used.

FIG. 4 shows a plurality of tubes 40 having a triangular cross section bundled together in a pyramid shape, with electrodes 41 and 42 formed at both ends. According to this structure, like the one in FIG.
Not only the inner surface of the continuous passage 43 of 0, but also the gap 44 formed between the plurality of adjacent cylinders 40 can be used as a secondary electron multiplication surface.

FIG. 5 shows a plurality of cylinders 50 twisted together, with electrodes 51 and 52 formed at both ends. Compared to the linear tube 1 shown in FIG. 1, this tube 50 can suppress positive feedback of opposite polarity particles (for example, cations with respect to incoming electrons) from the collector side, and also has a smaller apparent length. The effective length of the continuous path 53 can be increased, the operation can be further stabilized, and the secondary electron multiplication gain can be increased.

FIG. 6 shows a bundle of tubes 60 having a substantially hexagonal outer diameter in cross section, and electrodes 61 and 62 are formed at both ends. On the outer surface of this cylinder 60, grooves each having a hexagonal side with a cross section of 1/4 circle are formed at every corner in the axial direction. therefore,
Not only the continuous passage 63 of the cylinder 60 but also the gap 64 formed between adjacent cylinders 60 can be used as a secondary electron multiplication surface.
Furthermore, since the cross section is uniform, it is particularly suitable for applications such as image intensifier tubes, which require uniformity and regularity of picture elements.

FIG. 7 shows a bundle of tubes 70 having a continuous passage 73 and a hexagonal outer diameter in cross section. Electrodes 71 and 72 are formed at both ends, and there is a gap between adjacent tubes 70. It is the one that has been eliminated.

Note that the various examples shown in FIGS. 6 and 7 may also be used by being twisted as shown in FIG. 5, if necessary.

In FIG. 8, a plurality of continuous passages 83 are formed perpendicularly to the electrodes 81 and 82 in a plate-like body 80 made of semiconductor ceramics with electrodes 81 and 82 formed at both ends.

[Brief explanation of drawings]

FIG. 1 is an experimental circuit diagram for measuring secondary electron multiplication gain. FIGS. 2 to 8 are perspective views showing structural examples of a secondary electron multiplier using the semiconductor ceramic for a secondary electron multiplier according to the present invention. 1.30.40.50.60.70 is a cylinder made of zinc oxide-copper oxide semiconductor porcelain or zinc oxide-titanium oxide-copper oxide semiconductor porcelain, 20 is zinc oxide-copper oxide semiconductor porcelain or zinc oxide- A flat plate made of titanium oxide-copper oxide semiconductor porcelain, and 80 a plate-shaped body made of zinc oxide-copper oxide semiconductor porcelain or zinc oxide-titanium oxide-copper oxide semiconductor porcelain.

Claims (2)

[Claims] (1) A semiconductor ceramic composition for a secondary electron multiplier, characterized by comprising a zinc oxide-copper oxide semiconductor ceramic. (2) A semiconductor ceramic composition for a secondary electron multiplier, characterized by comprising a zinc oxide-titanium oxide-copper oxide semiconductor ceramic.